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101.
Abstract The aim of this study was to assess the effect of land application of sewage sludge on phosphorus (P) losses during intense rainfall. Three rainfall simulations (40 mm h?1 of 30 min duration) were conducted on a field amended with sewage sludge. The overland flow water (OFW) was monitored and sampled every minute. The suspended solid, the dissolved and total phosphorus (respectively SS, TP and DP) concentrations were analysed. The forms of particulate bound P (PP) were investigated. Several results stem from this experiment: (a) sludge application induced a large increase in the DP content of the OFW; the concentrations obtained (0.15–0.57 mg l?1) were shown to result from desorption processes from the SS; and (b) in contrast, sludge application affected neither the SS content nor the TP concentration of OFW (9.5 g mg l?1 P, consisting of PP for 95%). However, sludge preserved the structure of soil surface and led to a 45% decrease in runoff rate (150 m3 ha?1 collected on the test surface compared to 290 m3 ha?1 on a reference). This indirectly reduced TP losses (2.7 kg ha?1 on the reference surface compared to 1.4 kg ha?1 on the test surface). 相似文献
102.
Abstract Agricultural watersheds in the Czech Republic are one of the primary sources of non-point-source phosphorus (P) loads in receiving waters. Since such non-point sources are generally located in headwater catchments, streamflow and P concentration data are sparse. We show how very short daily streamflow and P concentration records can be combined with nearby longer existing daily streamflow records to result in reliable estimates of daily and annual P concentrations and loads. Maintenance of variance streamflow record extension methods (MOVE) can be employed to extend short streamflow records. Constituent load regressions are used to predict daily P constituent loads from streamflow and other time varying characteristics. Annual P loads are then estimated for individual watersheds. Resulting annual P load estimates ranged from 0.21 to 95.4 kg year-1 with a mean value of 11.77 kg year-1. Similarly annual P yield estimates ranged from 0.01 to 0.3 kg ha-1 year-1 with an average yield of 0.07 kg ha-1 year-1. We document how short records of daily streamflow and P concentrations can be combined with a national network of daily streamflow records in the Czech Republic to arrive at meaningful and reliable estimates of annual P loads for small agricultural watersheds. Citation Beránková, T., Vogel, R. M., Fiala, D. & Rosendorf, P. (2010) Estimation of phosphorus loads with sparse data for agricultural watersheds in the Czech Republic. Hydrol. Sci. J. 55(8), 1417–1426. 相似文献
103.
《水文科学杂志》2013,58(4):834-843
Abstract Water quality in the Paso Piedras Reservoir has deteriorated, primarily due to periodic blue-green algal blooms, making it temporarily unfit for human consumption. This phenomenon results from the eutrophication of waters of the watershed, and nutrients are considered to be the primary contributors to degradation of freshwater quality. In order to reduce the levels of nitrogen and, most of all, phosphorus, entering the Paso Piedras Reservoir, it is necessary to understand the incidence of diffuse transfers of nutrients from agricultural soils. The nitrogen composition, soluble reactive phosphorus (SRP) and other physico-chemical parameters of the water were analysed in various different parts of the watershed in order to characterize water input to the reservoir from areas with different anthropogenic activity. The upper Sauce Grande basin was divided into three areas with different edaphic characteristics. The physico-chemical parameters measured in sampling surveys included: SRP, ammonium and nitrate, pH, conductivity, turbidity, and total solids. The results showed that the water of the Sauce Grande (areas 1 and 2) was not strongly contaminated, but in El Divisorio (Area 3, which is a sub-watershed whose stream flows directly into the Paso Piedras Reservoir), the levels of conductivity, total suspended sediments and SRP were so high that its contribution to the reservoir accounts for nearly 50% of the total SRP input. The main characteristics of El Divisorio watershed that make it a diffuse source of SRP were not only that its soils, under agricultural-livestock production, have significant slopes, so that water and wind erosion are faster, but also that human intervention had caused the destruction of aggregates. The results showed the influence of the soil characteristics, production systems and the micro-environment developed in the reservoir on the characteristics of waters flowing out of the reservoir. The two villages located in Area 2 had no significant influence on the concentration of nitrogen compounds and SRP found downstream. 相似文献
104.
为研究海水养殖对海湾沉积物的累积影响, 对大亚湾的大鹏澳养殖区沉积物柱状样中总氮、总磷和有机碳的含量及剖面分布特征进行了研究, 并探讨了海水养殖区沉积物中氮、磷的污染状况。结果表明, 网箱养殖区、贝类养殖区和对照区等3个区域柱状样中总氮的含量范围分别为638.2—3803.9mg.kg-1、740.9—2152.1mg.kg-1和343.2—471.9mg.kg-1, 总磷的含量范围分别为344.7—3233.9mg.kg-1、297.9—497.5mg.kg-1和650.2—1327.2 mg.kg-1, 有机碳的含量范围分别为0.96%—2.22%、0.87%—1.13%和0.69%—0.95%。该三个因子的含量均从底层至表层呈增加趋势, 但网箱养殖区上层增加幅度最为剧烈, 贝类区次之, 对照区变化幅度最小。所有柱状样中, 总氮含量均超标, 但网箱养殖区总氮污染最为严重, 贝类养殖区次之, 对照区最轻; 网箱养殖区的总磷在上层的不同深度超标, 而贝类养殖区及对照区柱状样的总磷含量均未超标。 相似文献
105.
John C. Panuska Laura Ward Good Peter A. Vadas Dennis L. Busch Asli Ozkaynak 《水文研究》2011,25(15):2329-2338
Phosphorus (P) export from agricultural lands above known threshold levels can result in adverse impacts to receiving water quality. Phosphorus loss occurs in dissolved and sediment‐bound, or particulate phosphorous (PP), forms, with the latter often dominating losses from row‐cropped systems. To target practices, land managers need good computer models and model developers need good monitoring data. Sediment monitoring data (e.g. radiometric finger printing and sediment P sorption capacity) can help identify sediment source areas and improve models, but require more sediment mass than is typically obtained by automatic sampling. This study compares a simple suspended sediment sampler developed at the University of Exeter (UE) with automatic sampling in intermittent channels draining corn and alfalfa fields. The corn field had a greater runoff coefficient (27%) than alfalfa (11%). No differences were found in enrichment ratios (sediment constituent/soil constituent) in PP (PPER) or percent loss on ignition (LOIER) between paired UE samplers on corn. The median LOIER for the UE samplers (1·9%) did not differ significantly (p > 0·13) from the automatic sampler (2·0%). The PPER from the UE samplers was on average 20% lower than the automatic samplers. A correlation (r2 = 0·75) was found between sediment PP and % LOI from automatic samplers and UE samplers for particles < 50 µm, while for > 50 µm PP concentration did not change with changes in % LOI. Sediment ammonium‐oxalate extractable metals were similarly related to LOI, with the strongest correlation for iron (r2 = 0·71) and magnesium (r2 = 0·70). Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
106.
INTRODUCTIONPhosphorus (P)isanimportantlimitingelementinglobaloceanicproductivity (Holland ,1 978) ,soknowledgeofPisakeytobetterunderstandingofthecyclingofcarbon ,nitrogen,sulfur,andothernu trientelements.Inasimplemassbalancemodel,thelevelofdissolvedPintheoceanisafunctionoftherateofinputviarivers,andtherateofoutputviadepositioninsediments.Inthepresentstudy,thefocusisontheriverinePinputbytheHuangheRiver (YellowRiver)totheBohaiSea,andespeciallyontheamountofPsolubilizedfromsolidphasesupo… 相似文献
107.
The effect of drawdown on suspended solids and phosphorus export from Columbia Lake,Waterloo, Canada
Mike Shantz Elizabeth Dowsett Emma Canham Guillaume Tavernier Mike Stone Jonathan Price 《水文研究》2004,18(5):865-878
This study examines the effect of drawdown on the timing and magnitude of suspended solids and associated phosphorus export from a 12 ha reservoir located in an urbanized watershed in southern Ontario, Canada. Water level in Columbia Lake was lowered by 1·15 m over a 2‐week period in November 2001. The total phosphorus (TP) concentrations ranged from 63 to 486 µg L?1 in Columbia Lake and 71 to 373 µg L?1 at its outflow. All samples exceeded the Provincial Water Quality Objective of 30 µg TP L?1. Outflow concentrations of suspended solids and TP increased significantly with decreasing lake level and were attributed to the resuspension of cohesive bottom sediments that occurred at a critical threshold lake level (0·65 m below summer level). Suspended solids at the outflow consisted of flocculated cohesive materials with a median diameter (D50) of c. 5 µm. Particulate organic carbon accounted for 8·5% of the suspended solids export by mass. A total mass of 18·5 t of suspended solids and 62·6 kg TP was exported from Columbia Lake, which represents a significant pulse of sediment‐associated P to downstream environments each autumn during drawdown. The downstream impacts of this release can be minimized if the water level in Columbia Lake is lowered no more than 0·5 m below summer levels. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
108.
TRANSFERABLE PHOSPHORUS IN SEDIMENTS OF THE HUANGHE RIVER ESTUARY 'S ADJACENT WATERS 总被引:1,自引:0,他引:1
宋金明 《中国海洋湖沼学报》2001,19(1):81-86
Based on a new idea for research on cycling of marine biogenic elements, this study showed that only the leachable form phosphorus in natural grain sizes manne sediments constitutes the transferable phosphorous in the sediments. The transferable phosphorus content in the natural grain sizes surface sediments in the Huanghe River estuary adjacent waters ranges from 58.5-69.8 μg/g, accounting for only 9.1%-11.0% of the total phosphorus content, whereas the leachable form (“transferable” )phosphorus content in the sediment after it was totally ground into powder was found to be 454.8-529.2μg/g, accounting for 73.4%-89.1% of the total phosphorus. Analysis of the correlation between thebill,ass of benthos and the leachable form (“transferable” ) phosphorus showed that most of the leachableform (“transferable”) phosphorus in the totally ground sediment did not participate in the marine biogeo chemical cycling. Furthermore, a synchronous survey on benthos showed that the biornass of meio-and maero-benthos exhibited good positive correlation with the leachable form of phosphorus in the naturalgrain sizes sediment, but peorer correlation with the leachable form (“transferable”) phosphorus in the totally ground sediment, indicating that transferable phosphorus in marine sediment is the leachable form of phosphorus in the natural grain sizes sediments, and is not the previously known leachable form(“transferable”) phosphorus obtained from the totally ground sediment. 相似文献
109.
魏宽义 《地球科学与环境学报》1993,(4)
本文以构造变形为主线,将沿铁炉子断裂带侧旁的地质体划分为不同的构造均匀区段。解析了不同区段内的变形特征,总结了包括矿体就位方式和后期改造在内的综合地质事件演化序列。指出了铅锌矿的找矿方向及其它金属矿产的找矿线索。 相似文献
110.
INTRODUCTIONPhosphorusisanessentialdietarynutrientforlivingorganismsandhasanimportantroleincel lularfunction ,asitisanimportantcomponentofnucleicacids,phospholipid ,phosphoproteins,ATPandseveralimportantenzymes,andcoenzymes.Inaddition ,phosphateservesasab… 相似文献